Monomeric emulsion stabilizers

ABSTRACT

A novel class of monomeric emulsion stabilizers consists of certain types of ethylenically unsaturated radicals covalently linked to a quaternary nitrogen atom which in turn is covalently linked to a lipophilic radical. Such monomers will polymerize with other ethylenically unsaturated radicals forming selfstabilized, surfactant-free polymeric dispersions.

United States Patent Samour et al.

MONOMERIC EMULSION STABILIZERS Inventors: Carlos M. Samour, Wellesley Hills;

Mildred C. Richards, Wakefield, both of Mass.

The Kendall Company, Walpole, Mass.

Filed: Aug. 9, 1974 Appl. No.: 496,321

Related US. Application Data Division of Ser. No. 272,282, July 17, 1972, abandoned, which is a division of Ser. No. 867,899,

Assignee:

I Oct. 20, 1969, Pat; No. 3,780,092.

us. Cl. 260/482 P; 260/459; 260/470; 260/471 A; 260/481 R; 260/482 R; 260/485 Int. Cl. C07C 101/20 Field of Search 260/485 H, 485 J, 482 P,

260/482 R, 470, 471 A, 481 R, 459

[ Dec. 23, 1975 [56] References Cited UNITED STATES PATENTS 3,787,474 1/1974 Daniels et al. 260/485 l-l Primary Examiner-Lorraine A. Weinberger Assistant Examiner-E. Jane Skelly [5 7] ABSTRACT 3 Claims, No Drawings Alternatively, it may be of nonionic type as represented MONOMERIC EMULSION STABILIZERS This is a division of copending application Ser. No. 272,282, filed July 17, 1972, now abandoned, which in 5 turn is a division of our application Ser. No. 867,899, filed Oct. 20, 1969, now US. Pat. No. 3,780,092.

This invention relates to stabilizing agents for emulsion polymerization. More particularly it relates to a class of quaternized organic salts which serve simultaneously as stabilizing agents for emulsion polymerizations and as monomeric reactants in the polymerization, so that the salts become an integral part of the polymer, which is thereby self-stabilized without the use of surfactants.

Polymeric latices, derived from ethylenically unsaturated monomers, are widely used for a variety of applications, such as adhesive masses and binders for nonwoven fabrics. Most conventional polymeric latices are produced by an emulsion polymerization process, in which monomeric materials are polymerized while they are dispersed in an aqueous medium by means of a surface active agent. The surface active agent may be anionic in nature, such as soap or sodium lauryl sulfate.

by various ethylene oxide derivatives, or by polyhydroxy compounds, or it may be cationic, as represented by alkyl ammonium halides. Cationic agents are preferably combined with a nonionic agent for improved performance. The polymerization of monomeric materials is also frequently effected in the presence of water-soluble protective colloids or stabilizing agents. Any of the above emulsifying or stabilizing agents leads to the presence of a water-sensitive ingredient in the final polymeric latex. For latex utilizations wherein wet strength and resistance to the influence of water are desirable, as in most paper coatings nonwoven fabrics, certain pressure-sensitive adhesive tapes, and the like, the presence of a water-sensitive ingredient in the polymeric mass is undesirable.

A preferred method of avoiding the presence of water-sensitive elements in a polymeric latex is to employ what is termed herein monomeric emulsion stabilizers that is, a classof organic monomer which co-polymerize with the ethylenically-unsaturated monomers, becoming a part of the final polymer, but which stabilize the polymerization process against the formation of coagulum and against subsequent phase separation. Such monomeric emulsion stabilizers may be cationically-charged nitrogen compounds as set forth in my US. Pat. No. 3,399,159 wherein the use of monomers such as vinyl pyridines, acid-amines, and certain nitrogencontaining acrylic derivatives is described.

Also, in my copending application Ser. No. 769,355, filed Oct. 21, 1968, now abandoned, there is described a process for preparing monomeric emulsion stabilizers containing a quaternized nitrogen atom ionically linked to an acidic group, such as a sulfate, sulfite, sulfonate, or phosphate, which acid group is convalently bonded to a lipophilic group of eight to 24 carbon atoms.

It is an object of the present invention to prepare a new and useful class of monomeric emulsion stabilizers containing a quaternized nitrogen atom covalently linked to an ethylenically unsaturated radical and to a lipophilic group, and ionically linked to an anionic group.

It is a further object of the invention to prepare a new and useful species of self'stabilized, surfactant-free polymeric emulsion suitable for use as coatings, binding agents for nonwoven fabrics, adhesives, and the like. Other objects of the invention will be apparent from the following specification and claims.

It has now been found that the polymerization of ethylenically unsaturated monomers may be advantageously carried out if a major portion of such a monomer or mixture of monomers is copolymerized with a minor proportion of a quaternized monomer of the general formula:

where V is an ethylenically-unsaturated radical selected from the following three classes:

a. acid ester groups or acid amido groups derived from the dicarboxylic unsaturated acids maleic, fumaric, citraconic, or itaconic, such as HO- COCH=CHCOO--, HOCO-CH=)\ CH-CONH--, HOCO-CH =C(CH- :;)COO, HOCOCH=C(CH=;)CONH,

CH2 CH2 b. acrylic ester or acrylamido groups represented by the formulas CH =CR -COO and CH =CR CONH, where R is H or CH 0. allyl, CH =CH-CH methallyl,

CH CHCH OCOCH and methallyl acetoxy, CH =C(CH )CH OCOCH In the formula given above, the A moiety of the monomeric emulsion stabilizer is zero when V is allyl, methallyl, vinyl acetoxy, ally] acetoxy, or methallyl acetoxy. Otherwise, A is a divalent radical selected from the classes consisting of a. ethylene, CH CH propylene, CH CH- )-OCOR;,; a polyalky'lene oxide group such as OOH -CHR (OCH CHR,)nR where R, is H or CH,-, and n is 0 to 4; an alkyl acetoxy or alkyl acetamido group such as CH COOR and CH- -CONHR;,; alkyl alkylene ethers such -CH- OR;,; and alkyl amides such CH CH(CH -,)-NH-COR;,. The lipophilic radical R may be linear or branched, saturated or unsaturated.

1n the preferred embodiments of the invention, R is an alkyl or benzyl group of from one to seven carbon atoms, and R is either an alkyl or benzyl group of from one to seven carbon atoms or a group selected from the class consisting of R OCOCH and R,-,N- H-COCH where R is H or an alkyl group of from one to four carbon atoms. Cases where R and R are lower alkyl groups, especially methyl groups, are preferred.

R and R may also be valence bonds of a cyclic amine of the piperidine or morpholine type,

1n the monomeric emulsion stabilizers of this invention, the X which is ionically linked to the quaternary nitrogen is an acid radical selected from the class consisting of F, Cl, Br, 1, CH SO C H SO and with Cl, Br, or CH SO preferred.

Typical reaction procedures for producing the monomeric emulsion stabilizers of this invention include the reaction of an appropriate ethylenically-unsaturated alkylene halide with a tertiary amine containing a lipophilic group or with an appropriate ring compound in which nitrogen is a ring member: or the reaction of a halogenated compound containing active halogen with an ethylenically-unsaturated compound containing a tertiary amine.

Representative preparations are the reactions between allyl chloride and dimethyl dodecyl amine or demethyl hexadecyl amine; between allyl bromide and N-cocomorpholine, in which the nitrogen atom in the morpholine ring is covalently bonded to a mixture of saturated alkyl groups averaging 12 carbon atoms; between dimethyl allyl amine and dodecyl chloroacetate; and between maleic anhydride and the reaction product of dimethylamino ethanol and lauryl bromide. Specific illustrations of these and other reactions will be given below in the following examples, together with illustrations of their use monomeric emulsion stabilizers.

EXAMPLE 1 Preparation and Use of Allyl Dodecyl Dimethyl Ammonium Chloride 23 grams of dimethyl dodecyl amine were dissolved in 31 grams of H 0 and 9 grams of allyl chloride were added. After 6 hours stirring at C some precipitation had occurred. grams more H O were added and stirring was continued for 16 hours, resulting in a slightly cloudy homogenous solution.

18 grams of this solution were dissolved in 290 grams of H 0, and 100 grams of ethyl acrylate were emulsified therein by gradual addition with stirring. The pH of the emulsion was about 6.0. It was cooled to 17C and 0.3 grams of 3% H 0 in H O were added, followed by the dropwise addition of a reductant solution (0.02 grams of ferrous ammonium sulfate and 0.5 grams of ascorbic acid in 10 grams of H 0). A nitrogen atmosphere was maintained throughout the polymerization in all examples, polymerization being initiated in the present instance after 1.8 grams of reductant solution had been added. The exotherm was 33C in about 2 minutes. Addition of 2 grams more reductant and 2 grams more of 3% H 0 after the reaction had cooled gave a 5C exotherm. The yield of polymer formed was over 90% of theoretical, and no coagulum was formed.

Essentially similar results were obtained when the ethyl acrylate was replaced by a mixture of 10 parts of ethyl acrylate and 74 parts of 2-ethylhexyl acrylate. The above procedure was also repeated using dimethyl hexadecyl amine in place of dimethyl dodecyl amine;

and using a mixture of 20 grams of vinyl acetate and grams of Z-ethylhexyl acrylate as the principal monomer.

EXAMPLE 2 28.8 grams of dimethylaminoethyl vinyl ether were dissolved in 98 grams of acrylonitrile. After cooling the solution to 15C, 69.3 grams of tridecylchloroacetate were added with stirring. Stirring was continued for 72 hours at 25C. Analysis showed 100% conversion to the quaternized ammonium chloride.

6 grams of the above solution were dissolved in 280 grams of H 0, to which was added with stirring a mixture of 80 grams of ethyl acrylate, 10 grams of butyl acrylate, and 7 grams of acrylonitrile. The pH of the resulting emulsion was between 5.0 and 5.5. The emulsion was cooled to 17C, after which polymerization was initiated and maintained using H 0 and reductant as in Example 1. There was no coagulum formed in the resulting polymeric emulsion, and the yield was 92% of theoretical.

EXAMPLE 3 Preparation and Use of Methacryloyloxyethyl Dimethyl Dodecyloxycarbonylmethyl Ammonium Chloride acrylate were added with stirring. The pH of the resulting emulsion was 6.0. It was cooled to 18C, and polymerization was initiated and maintained as in the above examples. The polymer yield was about If the proper equivalents of dimethylaminoethyl methacrylate and tridecylchloroacetate are used to form the quaternized compound, the resulting methacryloyloxyethyl dimethyl tridecyloxycarbonylmethyl ammonium chloride acts as a monomeric emulsion stabilizer similar to its dodecyl homolog.

EXAMPLE 4 Preparation and Use of Allyloxycarbonylmethyl Dimethyl Hexadecyl Ammonium Chloride 13.5 grams of allyl chloroacetate were added with stirring to 26.9 grams of dimethyl hexadecyl amine in 40 grams of dimethyl formamide. Two layers were initially formed, but with continued stirring for 16 ,hours at 25C, a clear, light yellow homogeneous solution was obtained. After 6 days standing, the solvent was removed under vacuum at 40C. The resultant solid was washed with ethyl ether and dried. The product was somewhat greasy, and analysis showed 97% of the theoretical chloride content-present.

Using the same general procedures as in the above examples, a mixture of 55 grams of vinyl acetate and 45 grams of butyl acrylate were emulsified using 3% of the weight of the above monomeric emulsifying agent, based on the weight of vinyl acetate and butyl acrylate, dissolved in 280 grams of H 0. Polymerization was initiated and maintained as above by the use of H and reductant. The yield of polymer was 83%.

EXAMPLE 5 Preparation and Use of Allyl Dodecylmorpholinium Bromide 91.3 grams of N-cocomorpholine and 45 grams of allyl bromide were stirred in 306 grams of H 0 at C for 24 hours. The clear, colorless solution contained 96% of the theoretical yield of quaternized ammonium salt.

5 grams of the above aqueous solution were dissolved in 1,000 grams of H 0, and a mixture of 160 grams of ethyl acrylate, 20 grams of acrylonitrile, and 20 grams of butyl acrylate were added with stirring. The resultant emulsion was polymerized by the use of 0.3 grams of t-butyl peroxy maleic acid and 4.1 grams of the ferrous ammonium sulfate-ascorbic acid reductant solution. The yield of polymer was 96% of theoret ical.

EXAMPLE 6 Preparation and Use of 3-(4-Hydroxymaleoyl)-aminopropyl Dimethyl Tridecyloxycarbonylmethyl Ammonium Chloride This quaternary compound was prepared in two stages. 20.4 grams of dimethylamino propylamine were mixed with 55.4 grams of tridecyl chloroacetate in 75.8 grams of acrylonitrile. After 72 hours at 25C, 90% of the theoretical chloride content was found in the form of the quaternized salt. The solution was cooled and 19.6 grams of crushed maleic anhydride were added, cooling being employed to keep the exothermic reaction below 22C. 100% of the theoretical chloride ion was found by analysis.

6 grams of the above solution were dissolved in 280 grams of H 0, and a mixture of 80 grams of ethyl acrylate, 10 grams of butyl acrylate, and 7 grams of acrylonitrile were added with stirring. The resulting emulsion,

pH 4.0 to 4.5, was cooled, and polymerization was initiated and maintained by the H O reductant system described in Example 1. Less than 1% of coagulum was formed, and the yield of polymer was 92%.

EXAMPLE 7 trile. After 24 hours at 25C, 9.8 grams of crushed 1 maleic anhydride were added to the clear solution. After 13 days standing, the separated crystalline compound was washed with ethyl acetate and dried.

2.25 grams of the quaternary salt were dissolved in 290 grams of H 0 and grams of ethyl acrylate were added with stirring. The resultant emulsion was poly merized with the H o -reductant system used in previous examples. The yield of polymer was 96% of theoretical.

When lauryl bromide was used in the initial quaternization reaction in place of p-dodecylbenzyl chloride, followed by reaction with maleic anhydride, 2-(4- hydroxymaleoyloxy)ethyl dimethyl dodecyl ammonium bromide was produced. Its behavior as a monomeric emulsion stabilizer in the polymerization of ethyl acrylate was essentially similar to the behavior of 2-(4- hydroxymaleoyloxy)ethyl dimethyl p-dodecylbenzyl ammonium chloride.

EXAMPLE 8 Preparation and Use of Methacryloyloxyethyl Dimethyl Hexadecyl Ammonium Bromide 19.3 grams of 2-bromethyl methacrylate and 27.8

grams of dimethyl hexadecylamine were mixed at 25C EXAMPLE 9 Preparation and Use of Allyl Dimethyl Tridecyloxycarbonylmethyl Ammonium Chloride 8.5 grams of dimethyl allylamine and 27.7 grams of tridecyl chloroacetate were mixed together in 36 grams of dimethyl formamide at 25C. After 15 days standing, petroleum ether was added to precipitate and isolate the crystalline product. Analysis showed that of the theoretical chloride content was in the form of the quaternized salt.

5 grams of the quaternized compound were dissolved in 290 grams of H 0, and 100 grams of ethyl acrylate were added with stirring. The resulting emulsion was polymerized by the customary H O reductant system. The yield of usable polymer was over When 26.3 grams of dodecyl chloroacetate were substituted for the 27.7 grams of the tridecyl chloroacetate, the dodecyl homolog of the above-described monomeric emulsion stabilizer was prepared. Its function and behavior are the same as that of the tridecyl compound.

EXAMPLE 10 Preparation and Use of Vinyloxyethyl Dimethyl p-Dodecylbenzyl Ammonium Chloride 11.5 grams of dimethylaminoethyl vinyl ether and 29.5 grams of p-dodecylbenzyl chloride were stirred together in 41 grams of acrylonitrile at 25C for 24 hours. The chloride by analysis was found to be completely quaternized.

2.5 grams of the above solution were dissolved in 700 grams of H 0. A mixture of 200 grams of ethyl acrylate, 25 grams of butyl acrylate, and 24 grams of acrylonitrile were added with stirring. The resultant emulsion was polymerized using a total of 35 grams of 3% H and l 1 grams of the reductant solution of Example 1. No coagulum was formed, and the polymer yield was 91% of theoretical.

EXAMPLE 1 1 Preparation and Use of 3-Methacryloyloxy 2-Hydroxypropyl Dimethyl Octadecyl Methyl Ammonium Sulfate Equimolar quantities of N-methyl-N-octadecyl amine and glycidyl methacrylate were reacted together in methanol to form methacryloyloxyhydroxypropyl methyl octadecyl amine. 14.3 grams of the resultant amine were dissolved in 20 grams of dimethyl formamide and 4.2 grams of dimethyl sulfate were added slowly with stirring. After 10 days standing at 25C, 9 grams of crystalline material was isolated, washed with ether, and dried. The sulfate band in the crystalline product was identified in the LR. spectrum.

2.25 grams of the above stabilizer were dissolved in 290 grams of H 0. 75 grams of ethyl acrylate were added with stirring. Polymerization was initiated and maintained by the usual H O reductant system. Less than 1 gram of coagulum formed, and the polymer yield was 96% of theoretical.

EXAMPLE 12 Preparation and Use of Allyl Hexadecyl Dimethyl Ammonium Fluoride Allyl hexadecyl dimethyl ammonium chloride was prepared by reacting allyl chloride and dimethyl hexadecyl amine as set forth in Example 1. 17.8 grams of the chloride in 23.5% aqueous solution were treated with a stoichiometric excess of AgF in aqueous solution until analysis of the filtrate showed only a trace of chloride ion present. Excess silver ion was removed by the careful addition of NaCl, AgCl being removed by filtration.

64 grams of ethyl acrylate, 8 grams of butyl acrylate, and 8 grams of acrylonitrile were emulsified by gradual addition with stirring to 2.4 grams (3% by weight) of the allyl hexadecyl dimethyl ammonium fluoride in 120 grams of H 0. The pH of the emulsion was about 6.0. It was cooled to 20C and 10 grams of 3% aqueous H 0 were added, followed by the dropwise addition of the reductant solution of Example 1 until polymerization was initiated after 5 grams of reductant has been added. The exotherm was C in 13 minutes. A total of 14 grams of reductant and 13 grams of aqueous H 0 were used to complete the polymerization. No coagulum was formed and the polymer yield was 95%.

EXAMPLE 13 Preparation of Allyl Hexadecyl Dimethyl Ammonium Iodide 16.8 grams of allyl iodide were dissolved in 44.6 grams of ethyl acetate and 27.8 grams of dimethyl hexadecyl amine were added slowly with stirring at 'room temperature. Within 15 minutes after the addition of the amine was complete, the viscosity of the solution increased and crystallization occurred. After 24 hours the crystals were filtered, washed with ethyl acetate, and dried. The colorless crystalline product contained 88% of the theoretical amount of iodide ion.

The proportion by weight of monomeric emulsion stabilizer used to stabilize the polymerization of other ethylenically-unsaturated monomers will depend on where R is a hydrogen atom or a methyl group, and R is a saturated alkyl radical of one to 14 carbon atoms. As is known in the art of preparing acrylic ester polymers. the softness of the polymer and the difficulty of initiating polymerization increase as the number of carbon atoms in the ester group increases. In the practice of this invention, when the acrylic monomer contains more than 8 carbon atoms in the ester group, it is advantageous to mix therewith at least about 20% of an acrylic ester with fewer than four carbon atoms in the ester group to initiate polymerization and enhance the stability of the dispersion. Therefore, esters in which the ester group contains from one to four carbon atoms are preferred.

Mixtures of more than one such ethylenically unsaturated monomer may be used, and in order to impart special properties of toughness, rigidity, or cross-linking reactivity to the polymer, a minor proportion, usually less than 20 mole percent, of the major monomer may be replaced by some other ethylenically unsaturated monomer such as vinyl esters, typified by vinyl laurate and vinyl stearate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl butyl ether; di-unsaturated monomers such as diethylene glycol diacrylate, ethylene glycol diitaconate, diallyl phthalate, divinyl benzene and the like; acrylic and methacrylic acids, acrylamide and methacrylamide, hydroxyethyl acrylate and methacrylate, and hydroxypropyl acrylate and methacrylate, and styrene.

Although the above examples using the stabilizers of this invention relate to batch processing, their use is equally well adapted to continuous polymerization processes.

Having thus described our invention, we claim:

9 1. Compounds corresponding to the formula R and R are selected from the class consisting of benzyl groups and alkyl groups of from one to V-AN* RX seven carbon atoms;

R R" R is selected from the class consisting of CH- l 5 COOR groups wherein R is a saturated aliphatic hydrocarbon group of from seven to 28 wherein V is selected from the class consistin of acid ester carbon atoms g and'X is a radical selected from the class consisting of groups and acid amido groups derived from maleic, Cr BF CH SO C H SO an d (HO-CO--CH=CHCOO and HO-- 1Q 3 4 2 5 4 CO-CH=CHCONH-- citraconic, HO CO-CH=C(CH3)COO and HO- CO--CH=C(Cl-l;,)CONH-), and itaconic acids (HO CO CH2 W COO and HO CO CH2 CONH |5 2. The product according to claim 1 wherein R and I fi R are methyl groups. CH CH 3. The compound according to claim 1 wherein the compound is 3-(4-hydroxymaleoyl)- aminopropyl di- A is selected from the class consisting of ethylene, methyl tridecyloxycarbonylmethyl ammonium chlopropylene, isopropylene, and hydroxypropylene ride. groups; 

1. COMPOUNDS CORRESPONDING TO THE FORMULA
 2. The product according to claim 1 wherein R1 and R2 are methyl groups.
 3. The compound according to claim 1 wherein the compound is 3-(4-hydroxymaleoyl)- aminopropyl dimethyl tridecyloxycarbonylmethyl ammonium chloride. 